Fused dropout cutout



April 3, 1951 D. c. HUBBARD FUSED DROPOUT CUTOUT 4 Sheets-Sheet 1 Filed May 6, 1949 April 3, 1951 D. c. HUBBARD 2,547,160

FUSED DROFOUT CUTOUT Filed May 6, 1949 4 Sheets-Sheet 2 April 1951 D. c, HUBBARD 2,547,160

FUSED DROPOUT CUTOUT Filed May 6, 1949 4 Sheets-Sheet 3 April 3, 1951 D. c. HUBBARD 2,547,160

FUSED DROPOUT CUTOUT Filed May 6, 1949 4 Sheets-Sheet 4 A?! 25 14a" as Patented Apr. 3, 1951 FUSED DROPOUT CUTOUT David C. Hubbard, Centralia, Ma, assignor to A. B. Chance Company, Centralia, Mo., a corporation of Missouri Application May 6, 1949, Serial No. 91,777

19 Claims. (Cl. 200-114) The present invention relates to fused drop-out cut-outs, and is particularly concerned with the provision of an improved cut-out having the following advantages.

1. The cut-out is adapted to use standard universal fuse links of any manufacture, according to conventional practice.

2. The cut-out is so constructed that it is pivoted at the upper end of the fuse unit, and the lower fuse tube contact is ejected from the bottom contact arm upon rupture of the fuse link so that the fuse tube will han with its opening downward after operation, thus protecting the interior of the fuse tube from all adverse weather conditions.

3. The actual physical parting of the lower contacts due to fuse link rupture, is delayed until after the arc has been extinguished within the fuse tube, thus preventing the arcing between the contacts.

4. The delaying of the actual parting of the lower contacts is accomplished by the following features:

(a) Requiring the ejector arm to travel eighty to ninety degrees before unlatching the lower contact.

(b) Providing a limited wiping contact after unlatching to delay the travel of the lower fuse tube contact out of engagement.

Using the jet action from the opening at the lower end of the fuse tube to react with the top trunnion to produce a torque that tends to hold the lower end of the fuse tube in engagement with its contact during the blast and therefore during the arcing period.

5. The cut-out is provided with an ejector arm which pulls the fuse link from the fuse tube, even though rupturing currents are too light to generate suflicient gases within the fiber tube to eject the link rapidly, thus providing a quick circuit break on light currents.

6. The present cut-out may be used as a disconnect because it is also pivoted at the lower contacts, and the upper contacts may be pulled apart while it pivots on its lower contacts to a downwardly hanging position, indicating it has been manually disengaged.

7. Re-fusing and manipulating the fuse tube unit is accomplished according to conventional practice in re-fusing similar types of cut-outs, r

since the fuse tube hangs from a disconnect stick and is first connected to the lower contact and then pivoted upward to engage the top contact.

8. The present cut-out is trip free because after it has been re-fused and has its lower con 2 tacts connected, the lower; end of the fuse unit is ready to be ejected if the fault still exists when the upper end is swung up into engagement with the top contact arm.

9. The fuse tube unit has a blast chute which offers a limited but effective protection to the operator in the event a short circuit still exists, as the blast chute directs the molten elements and force of the blast away from the face of the operator.

10. The mechanisms of the cut-out are so constructed that they are unaffected by ice accumulations, or are adequately protected from such accumulations as may occur.

11. Visual inspection of the cut-out device in open position indicates whether the device was operated automatically, indicating the existence of a fault, when the lower contacts are separated; and it indicates whether the device was opened manually, indicating the purposeful de-energization of the circuit for repairs or other reasons, when the upper contacts have been separated, these two operations involving the opposite ends of the fuse unit.

12. The cut-out has firm stops for arresting skyrocketing, which may be due to the jet action from the open end of the tube, so that the contact springs will not be overstressed.

13. Three points of contact are assured at the top and at the bottom support, regardless of the casting alignment, thus assuring good electrical contact with two wire springs, and at least one side of the casting.

14. The cut-out is provided with a biasing sprin which provides contact pressure in addition to the clip pressure, and also serves as a buffer to absorb a portion of the shock resulting from jet action on heavy short circuits.

15. Wiping contact on all the springs and trunnions keeps them in clean condition; and all closing stresses on fragile fuse elements have been eliminated, since no external force of any kind is appliedto the ejector arm during the placingof the fuse tube unit.

16. The blast chute tends to divert the high blasts of ionized gas which might otherwise mushroom back toward the lower contact support, where they might otherwise establish an arc across the supporting insulator.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar character of reference indicate similar parts throughout the several views.

Referring to the drawings, of which there are four sheets,

Fig. 1 is a side elevational view of a fused dropout cut-out embodyin my invention;

Fig. 2 is a top plan view; taken on the plane of the line 2-2 of Fig. 1, looking in the direction of the arrows;

Fig. 3 is a bottom plan view, taken on the plane of the line 33 of Fig. 1, looking in the direction of the arrows;

Fig. 4 is a bottom plan view of the contact housing;

Fig. 5 is a side elevational View of the contact housing, taken on the plane of the line 55 of Fig. 4, looking in the direction of the arrows;

Fig. 6 is a side elevational view of the spring retaining washer;

Fig. '7 is a plan view of said washer;

Fig. 8 is a side elevational View of one of the contact springs;

Fig. 9 i a front elevational View of the fuse tube unit, taken on the plane of the line 55 of Fig. 1, looking in the direction of the arrows;

Fig. 10 is a fragmentar sectional view, taken on the plane of the line iii-It of Fig. 9, looking in the direction of the arrows;

Fig. 11 is a fragmentary elevational view of the fuse tube unit, showing the position of its ejector arm after the fuse has been ruptured and ejected;

Fig. 12 is a top plan view of the lower contact bracket;

Fig. 13 is a sectional view of said bracket, taken on the plane of the line l3i3 of Fig. 12, looking in the direction of the arrows;

Fig. 14 is a fragmentary side elevational View of a modification;

Fig. 15 is a fragmentary bottom plan view of said modification;

Fig. 16 is a view in perspective of the contact housing of this modification.

Referring to Figs. 1 to 3, indicates an insulator, which is mounted by means of a bracket 2| upon a cross arm or other support at an angle, as shown. The present devices may be mounted upon a single insulator or upon a pair of insulators, the latter type of mounting being shown in my prior application on fused drop-out cut-outs, Ser. No. 11,076, filed February 26, 19%8.

In the embodiment selected to illustrate the invention, a single insulator 25 is used; and it is provided with end portions 22 of reduced diameter for receiving a clamping metal band 23 at the top of the insulator and another clamping band 2 at the bottom.

The clamping bands 23 and 25 are each pro-- vided with the partially cylindrical portion 25, which extends about the reduced cylindrical part 22 of the insulator and carries a pair of attaching flanges 225, 2'1. These attachin flanges are clamped together close to the insulator by a through bolt 23, which passes through apertures in the attaching flanges 25, 2'! and is provided. with a nut 29 for drawing the clamping band tightly about the insulator.

The attaching flanges 25, 2'5 extend parallel to each other toward the right in Fig. 2, where they are secured to the contact housing 36 by a pair of screw bolts El, 32 passing through registering apertures in the attaching flanges 26, 27 and in the contact housing (Fig. 5), as indicated at 33, 34.

The aperture 3% in the contact housing is preferably oval, being elongated in a direction transverse to the major axis of the housing 35 so that the contact housing may pivot on the bolt 3 i, due

to the clearance provided around the bolt 32 by the oval opening 34.

This permits automatic adjustment of the upper contact to compensate for differences in length of the fuse tube units 35 (Fig. 1), which may be caused by ordinary methods of manufacture.

The contact housing 3t may consist of a metal casting having a substantially flat upper body 35 and a pair of forwardly extending parallel legs 5'1, 38. The legs 5?, 38 are preferably angular in cross section, having a vertical flange 39 and an upper horizontal flange 40 in each case.-

The upper horizontal flange 46 merges into a deeper and thicker end portion M, which has a diagonally extending camming surface 42 leading to a partially cylindrical transverse groove 43. The groove 53 is bordered on its lower side (Fig. 5) with a longitudinally projecting lug 44.

The grooves 43 are of suitable size to provide a recess for receiving the cylindrical trunnions 55 carried by the upper contact fitting 46 of the fuse tube unit 35 (Fig. 1).

The camming surface 52 engages the top and advancing side of the trunnion 5 so that the contact housing 3&3 may pivot upward on bolt 31 to permit the trunnion to enter the roove 43, due to the camrning action of the trunnion on the surface 22.

The horizontal flanges of the contact houslllg 35 merge into the upper flat body 36, which also has a pair of depending vertical flanges 41, 38; and the space 49 between the legs 31, 38 is bounded at its base by a depending flange 50. The upper flat body 36 ha a pair of axially located apertures 5i for attachment of a spring 52, further to be described, and shown in Fig. 1.

These are formed in a depending enlargement of a depending reinforcing rib 53. The flat body 36 extends backwardly beyond the ribs 51, %8, having a tail portion 513 with a depending spring engaging end 55. that is, transverse to the tail portion 54.

The spring engaging end 55 engages a spring 55, preferably a leaf spring, which is carried by bolts 28 and 8!, as shown in Fig. l. The leaf spring 55 has an initial tension in an upward direction to urge the contact housing 35 in a clockwise direction about the bolt 3 i.

The spring 56 has a U-shaped end portion 51 at each end, for extending about the bolts 28 and (ii, and by means of which it is retained on the bolts.

The contact housing 35 also carries a pair of contact springs shown in Fig. 8, constructed of resilient wire. The prings 58 have a straight portion 55, which terminates in a single spiral loop for receiving the screw bolt 32. The spring continues with a short straight portion 61 and a U-shaped end portion 52, which is of sufficient size and in proper location to extend about the bolt 5.

At its, forward end the straight portions 59 have an easy curvature at 53 and have diagonally outwardly extending portions 55. The straight portion =55 extends diagonally inward from its point of attachment to the bolt 32, which passes through the loop 69; and the straight portion 59 is located. immediately below the groove 53 in each case, being substantially parallel to the thickened portion M at that point.

The outwardly flaring diagonal portions 64 serve to engage and guid the upper contact fitting 46 of the fuse tube unit 35 into a position be- 'in place by a plurality of pins or rivets 19.

which the end of the tube abuts.

tween the legs 31, 38 of the contact housing 30 and between two of the springs 58. The same bolts 3| and 32 which secure the contact housing to the attaching flanges 26, 21, clamp the spring 58 against the side of the contact housing at the flanges 41, 48.

Springs 58 also have an initial tension, tending to close toward the grooves 43 of the contact housing So that the springs 58 must be spread away from the grooved portions 43, to permit the trunnions 45 to enter the grooves 43.

The bolt 3I pr-eferably'supports a special washer plate 65 (Figs. 6, Fig. 7), which comprises a rectangular metal member having a through bore 66 for the bolt and having a tubular lug 51a for receiving the hook formation 62 of the spring 58.

In addition to the tubular formation, thi plate supports a rib 6? on the same side as the tubular formation for engaging outside of th hook 62 of the spring; and it preferably has a connector flange B8 on the opposite side of the plate for use in securing a conductor, such as a tap wire.

The conductor goes in between the washer 69 and. the plate 65, and is secured by the nut I8, thus providing an electrical connection to the upper contact arm, contact housing 39, and to the springs 58. The headed end of the bolt 3I preferably supports a similar washer plate 65; and both the springs and the contact housing are in good electrical conducting relation to the tap wire.

The fuse tube unit 35 is provided at its upper end with a contact fixture es, comprising a tubular body II for receiving the insulating tube I2, which may be secured in place by a plurality of transverse riveted pins I3, preferably so located that they are received in grooves in the side of the insulating tube I2, while passing completely through the tubular member I i.

The tubular member ll has a laterally extending flange M, which is provided with a ring 2'5 for engagement with a clamp stick or with the laterally projecting lug on the end of a disconnect stick. The hole in the ring '55 is large enough to pass. the head on the lug of the disconnect stick.

The contact fixture it is provided at its right side in Fig. 2 with a pair of cylindrical trunnions 45, these trunnions forming an integral part of the tubular member TI and flange l4, and projecting oppositely and axially with respect to each other. that the screw cap 1%, which may be threaded into the tubular member I I, secures the button that is usually carried by the upper end of the fuse cable.

The top of the cap is flat, thus providing an outer corner 35a, Fig. which engages a complementary latching shoulder 16?) on spring 52. Spring 52 is a leaf spring having one end secured to the contact housing at holes 5! by rivets 5| a, and it extends above the groove between the legs 31, 38 and is tensioned downward against the end of the fuse unit 35.

When the fus unit swings from the full line position of Fig. 1 to the dotted line position, spring '52 latches the fuse unit in the dotted line position,

preventing it from swinging in the wind.

At its lower end the fuse'tube unit carries a lower contact fixture ll, comprising a cast metal body formed with a tubular portion '58 having a bore for receiving the insulating tube 12, which is open at its. lower end. The tube is again secured Below the insulating tube I2 the contact fixture T! is formed with a partition wall 8!! (Fig. 10), against The contact fixture 4 .5 is so constructed This wall has be flat and parallel, both extending downwardly.

The rear wall 36 preferably curves toward the right, and terminates with its lower edge approximately at the axis of the tube T2 so that the cable may clear the rear wall 86, while still being located in the axis of the tube I2.

The blast chute, comprising the walls 83-86, directs the explosive discharge, which comes out of the lower end of the fuse tube, away from the face of the operator, who is usually toward the left, in Fig. 10, with respect to this blast chute.

The lower contact fixture l1 has an integral tubular spring housing Bl, which extends diagonally downward, toward the left, in Fig. '11. This is joined to the rear wall 8| of the blast chute by a reinforcing flange t3, which may carry a threaded lug 88 and a nut $9 for clamping the end of the fuse cable 95 (Fig. 1G). i

The tubular spring housing I supports a pair of integral laterally projecting trunnions 92, which are cylindrical and located on the same axis on the opposite sides of the fixture TI. The trunnions are located laterally with respect to the tube i2; and thus, when the jet action of the escaping gases from the bottom of the tube I2 reacts upon the fuse tube unit, the trunnions 92 are urged upward, which is resisted by suitable stops, further to be described; and the top end of the fuse tube unit is urged in a counterclockwise direction, to maintain its engagement with the upper contact housing 38 and contact springs The tubular spring housing 8! is provided with a lower slot 93 to the left of the trunnions 92 for permitting a wider range of movement of the ejector lever 94. At its upper side the spring housing 81 is again slotted adjacent its left end 95 and provided with a pair of upwardly extend ing flat walls 96, 9'! joined by a curved yoke 98.

These integral parts of the lower fixture 11 are for the purpose of pivotally supporting the ejector lever 94, which is pivoted upon a through pin or rivet 99 passing through the flanges 96, 91.

The extreme end of the yoke 88 at the point I serves as a stop for engaging the curved end portion IIJI of the ejector lever, limiting its clockwise rotation. The yoke 98, which. joins the pivot flanges 98, Sl, is also integrally joined to a reinforcing flange I82, extending over' toward and joining with the spring housing 81.

This reinforcing flange has a relatively large through bore I03, forming another lifting ring for engagement with a clamp stick or disconnect stick.

The spring housing 8! has a cylindrical bore It! for receiving the helical compression spring I05. This spring is seated at its right end against the base I88 of the bore I84. At its other end it bears against a washer I87, which has a slot or aperture I08 for receiving the end of a strut I09.

The strut N19 has a smal er portion to go in the aperture H38 and a shoulder resting against the washer Illl', by which it is permitted a limited amount of pivotal movement. At its other end, Ill, it has a longitudinal slot separating two legs; and the slot receives the flanged portion I I I (Fig. 11) of the ejector lever.

' The spring has an initial compression so that it constantly urges the ejector lever 94 toward the position of Fig. 11. The ejector lever 9t may comprise a cast metal member of generally triangular shape provided with a central flat web H2 surrounded by a border flange IE3, which projects from both sides of the web H2.

The ejector lever 9 is generally triangular, tapering toward its free end He, where it is provided with a laterally projecting hook H5, having a groove IIE on its lower side for receiving the leader cable 9i. The leader cable Ill, which depends from 'the fuse in the tube l2, goes out the lower end of the tube and blast chute, passes over the end of the ejector lever 94 in the groove H5 of hook I15. From groove N6, the cable passes about a pin Ilsa located as close as possible to the pivot of the ejector lever, and is then wrapped around the threaded member 89 and clamped by the nut 90 with the ejector lever in the position of Fig. 10, where it is compressing the spring and located at its uppermost position.

The upper end of the ejector lever has a curved surface Iili of gradually increasing curvature,

this curved end eytending about the aperture for the pivot pin 99, and terminating at ill, adjacent the flat portion ill that is engaged by the spring strut M9.

The ejector lever 94 is thus always ready to pull the cable out of the tube when the tube has been re-fused, as shown in Fig. 1. Even when the fault is caused by a relatively low current,

which melts the fuse slowly and doesnot provide suflicient blast to eject the cable, the cable ejector lever will pull the cable out quickly, breaking the circuit inside the tube 12, before the circuit is broken mechanically by the lower contact fixture outside of the tube.

The curved surface IQI of the ejector lever also serves as a camming surface for engaging the back wall N8 of the lower contact housing IE9 to cam the fuse tube unit away from the lower contact housing I I9, as will be further described.

Referring now to Figs. 12 and 13, these are views of the top and of a section of the lower contact housing l I9. This lower contact housing may consist of a metal casting, which has a pair of legs I20, IZI, each of which has a thin vertical flange I22 and a laterally projecting horizontal reinforcing flange I23.

These flanges extend from end to end of the lower contact housing H9, except that the vertical flange I22 terminates at the forward trunnion groove I25. This trunnion groove is substantially half cylindrical and also extends into a thickened portion 225 of the horizontal flange I23 so that the groove I24 will extend under the trunnion and toward the left of the trunnion in Fig. 13.

When the contact housing I I9 is disposed at an angle, as shown in Fig. 1, the corner I26of the trunnion groove or bearing I23 extends upwardly into the path of the trunnion as the trunnion goes into or out of the groove I24. In other words, the angular installation of the fused cutout places the contact housing iii! in such position that the corner I26 forms only a slight obstruction to the movement of the lower trunnions 92.

The groove I2 5 forms a bearing for the trunnion 92 on its lower side and back side of the trunnion 92; and the corner I26 provides a latch ing shoulder to hold the trunnion in place; but the trunnion can be cammed over the latching shoulder I26, if force is exerted, to push the fuse 8 tube unit toward the right, away from the contact housing I I9.

The extreme right end I21 of the contact housing I I9 is preferably rounded to act in the man nor of a cam, to urge the trunnion 92 upward when it is struck by the trunnion 92.

The two legs i2ll and I2! of the contact housing H9 are joined by the back wall or partition I 58, previously mentioned, and by a bottom yoke I28. The partition or back wall Ilfiextends upward and curves toward the right at I29. It is thus located to be engaged by the curved camming surface Ifil on the ejector lever 94, while the upper curved part I29 overhangs the yoke 98.

The part I29 serves as a stop, preventing the lower contact fixture from moving upward when the jet action occurs out of the lower end of the tube 72. This stop prevents the jet action from overstressing the contact springs.

The vertical flanges l22 are provided with a pair of apertures I36, 231 for receiving the screw bolts I32, I33 (Fig. 3), which are provided with similar washer plates 65, washers $9, and nuts it. Thus the bolt I32 may pass through the attaching flanges 2t, 27 of the lower clamping band 24 and through the contact housing and may also serve as a connector to secure a tap wire or other lead by means of which electrical current is conducted to or from the cut,- out.

These bolts also support the lower contact springs 58, which are identical in shape to those previously described; but are inverted in position. Thus the contact springs 58 of the bottom contact housing 353 have the loop turned downwardly, the straight portion 59 running along the upper part of the contact housing on either side of the vertical flanges I22.

The contact springs are again given initial tension toward the trunnion 92 and toward the groove I2 5 so that they tend to close the groove; and the contact spring is cammed upwardly by the trunnion 92, which engages the upwardly main body of which is rectangular in cross section and provided at its top with laterally projecting reinforcing ribs I37.

The body supports a pair of legs I38, I39, also T-shaped in cross section; but the top flange becomes thicker at the end portion Hill, where it has the downwardly open trunnion groove H. To the right of this trunnion groove there is a curved camming portion M2, to be engaged by the trunnion so that the trunnion will be carnmed downward until it rides over into the groove MI.

The clamping band 25 in this case has its attaching flanges 26, Zl at a greater spread; but they are again secured by a through bolt 28 and have apertures for passing the two securing bolts MS, I 44.

The wire spring contacts I45, I46 may be similar in shape to those previously described, ex-

2; cept that the single turn 60a has its coils spread apart far enough so that the straight portion 59a. extends under the grooves MI, while the hook 62a is disposed inwardly in a plane so that it can engage the side of the rectangular shank body I36.

The ends of the spring contacts M5, i l-5 are clamped under plates 2:11, which have embracing flanges Hit above and below the hook 52a, where the plates are clamped by extra nuts I49. The attaching flanges 25, 21' are on the same bolts outside of these nuts, where they are secured by additional nuts I53.

The shank 136 of the contact housing :35 in this case has a vertical hole IEI for passing the screw bolt I52, which also goes through a U- shaped connector plate I53. The conductor or tap-off wire I54 has its end formed into a hook or loop, passing about the bolt I52 inside the flanges of the connector plate I53 by means of which it is tightly clamped to the horizontal flange I3! of the contact housing I35.

All of the other details of the construction of the fuse unit or contacts may be the same as previously described.

The operation of the present fused cut-out is as follows. When the fuse tube unit has been provided with a new fuse, installed as shown in Fig. 1, the fuse tube unit is then hung by means of its lower ring H33 on the laterally projectinglug of a disconnect stick. It then hangs down like the lower dotted line position of Fig. l, and may be moved over until its trunnions 92 engage below the curved surfaces I34 of the lower contact springs 59.

The fuse tube unit may be moved toward the lower contact housing until its trunnion 92 enters into the lower grooves I24, camming over thecorner I25, where the trunnions are retained by the downward spring pressure of the springs proaching the upper contact housing 35, the

trunnion 45 will engage the camrning surface 42 and cause this contact housing to be cammed upupwardly, the tail end 55 flexing the spring 56 as the upper contact housin pivots on the bolt I32. Thus provision has been made for fuse tube units in which the trunnions B2 and 45 may be at greater or less spacing, due to the inaccuracies of manufacture.

which is tensioned by the ejector lever spring M5, is pulled out of the tube I2 by the ejector lever 94. This ejector lever is held in its tensioned position of Fig. 1 by the cable and fuse; and upon rupture of the fuse the ejector lever pivots clockwise from the position of Fig. 1 to that of Fig. 11.

In addition to pullting out the fuse-leader, the

1 ejector 'lever has its curved camming surface It! engaging the back wall H3 of the lower contact housing. As the ejector lever pivots down to the position of Fig. 11, surface IDI forces the lower end of the fuse tube unit toward the right; and the trunnions 92 are forced toward the right, out of the grooves I24, until they are free of the lower contact arm. I

Then the fuse tube unit 35 pivots counterclockwise in Fig. 1 on the upper trunnions d5 until it is in the upper dotted line position. When the fuse tube unit hangs down'from its upper contact arm, this is an indication that the circuit has been ruptured, due to a fault.

It should also be noted that as the fuse tube unit is swung into place at its upper end the lower end is always free to be ejected, if a fault should occur, or if the fault should still exist.

Thus the cut-out is trip free at its lower end, even while being installed at its upper end.

It will thus be observed that I have invented an improved drop-out cut-out which assures the extinguishment of the are before the actual part- When the upper trunnion passes into the groove 43, it is retained there by the corner I54 (Fig. 5) and by the upper contact spring 58, which holds the trunnion in its groove.

The present cut-out may be used as an ordinary disconnect by merely placing a disconnect stick in the upper ring I5 and pulling the upper trunnions 45 out of the groove 43. Then the fuse tube unit 35 will swing on the lower trunnions 92 to the lower dotted line position. When the fuse tube unit is in this position, it indcates the purposeful disconnection which might be for,

are parted at the fuse; and the lower leader, i.

iii

ing of the lower contacts; and this is brought about by increased travel of the ejector arm, wiping contact to delay the opening movement and keep the contacts clean, and by causing the jet action to hold the contacts in engagement with each other until the blast and the arcing period have terminated. V

The present cut-out may be used bothas a manual disconnect and for the automatic opening of the circuit on existence of faults; but in either case the position of the fuse tube unit, after opening of the circuit, indicates whether it has been opened manuallyor automatically.

The present device is trip free, since the automatic opening may occur at the bottom, if the fault still exists, even while the operator is closing the top; and the blast chute diverts the major force of the blast away from the operator. Better contact is assured over the devices of the prior art, regardless of casting alignment; and all closing stress on the fragile fuse elements has been substantially eliminated.

It is an additional advantage that the present cut-out utilizes standard fuse links made by many manufacturers; and in its installation it is handled in the same manner as is conventional with many devices of different construction, thus eliminating the necessity for learning any new technique.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of the invention, and I do not wish to be limited to the precise details of construction set forth, but

" desire to avail myself of all changes within th scope of the appended claims. 1

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States, is:.

1. In a fused drop-out cut-out, the combina tion of an insulating support with a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cylindrical grooves for engagement with contact trunasev, mo

nions carried by a fuse tube unit, the said partially cylindrical grooves being open on the side toward each other, and the contact arms having their grooves located to engage those parts of the trunnions which are outermost with respect to the fused tube, a fuse tube unit comprising an insulating tube for receiving a fuse, and upper and lower contact fixtures carried by said tube and bearing trunnions on each fixture, one oi said contact arms having a pivotal mounting with a limited pivotal movement, to permit a spread of the contact arms relative to each other, and resilient means carried by said contact arm, for urging the same in a pivotal direction toward the other contact arm so that provision is made for receiving the trunnions of fuse tube units of different relative spacings which may occur due to inaccuracies of manufacture, the said resilient means comprising aleaf spring supported at both of its ends and engaged between its ends by a part of the pivotally mounted contact arm.

2. In a fuse tube assembly for a fused drop-out cut-out, the combination of an insulating support with a pair of outwardly extending contact arms carried by said support, and havin partial bearings for receiving trunnions opposing each other, an insulating tube with a contact fixture at its upper end and a contact fixture at its lower end,

the said up er contact fixture comprising a body having a bore for receiving the insulating tube, and having a pair of oppositely extending trunnions carried by said body outwardly of the body with respect to the location of the tube so that jet action occurring from the bottom of the tube will tend to cause the tube to pivot on said outwardly located trunnions in ,such manner as to keep the lower contact fixture in engagement with another contact arm.

3. In a fuse tube assembly for a fused drop-out cut-out, the combination of an insulating support with a pair pf outwardly extending contact arms carried by said support, and having partial bearings for receiving trunnions opposing each other, an insulating tube with a contact fixture at its upper end and a contact fixture at its lower end,

the said upper contact fixture comprising a body having a bore for receiving the insulating tube, and having a pair of oppositely extending trunnions carried by said body outwardly'of the body with respect to the location of the tube so that jet action occurring from the bottom of the tube will tend to cause the tube to pivot on said outwardly located trunnions in such manner as to keep the lower contact fixture in engagement with another contact arm, the said upper contact fixture also having a laterally and outwardly extending flange carrying a ring for engagement with a disconnect stick or the like.

4. In a contact arm structure for a fused dropout cut-out, the combination .of an insulator with a clamping band embracing said insulator, said band having a pair of attaching flanges, and means to draw said flanges together to clamp said band on said insulator, with a contact housing member comprising a metal member having a body provided with a pair of apertures, and threaded members passing through said apertures and attaching flanges to secure the contact housing to said clamping band and insulator, said contact housing having a pair of forwardly extending parallel legs, and each leg bein provided with a partially cylindrical groove for engagement with the trunnion of a fuse tube unit, when the fuse tube unit is located between said legs, the said threaded members also supporting on each side of said contact housing a resilient spring, each of said springs having a curved portion for engagement about each of said threaded members, and having a forwardly projecting portion which extends over and beyond said groove in position so that the forwardly extending portions of said springs are spread from the grooves by the trunnions of the fuse tube unit as the trunnions move into said groove, where they are held by said springs.

6. in a contact arm structure for a fused dropout cut-out, the combination of an insulator with a clampin band embracing said insulator, said band having a pair of attaching flanges, and means to draw said flanges together to clamp said band on said insulator, with a contact housing member comprising a metal member having a body provided with a pair of apertures, and threaded members passing through said apertures and attaching flanges to secure the contact housing to said clamping band and insulator, said contact housing having a pair of forwardly extending parallel legs, and each leg being provided with a partially cylindrical groove for engagement with the trunnion of a fuse tube unit, when the fuse tube unit is located between said legs, the said threaded members also supporting on each side of said contact housing a resilient spring, each of said springs having a curved portion for engagement about each of said threaded members, and having a forwardly projecting portion which extends over and beyond said groove in position so that the forwardly extending portions of said springs are spread from the grooves by the trunnions of the fuse tube unit as the trunnions move into said groove, where they are held by said springs, the said springs being bent outwardly and away from the contact housing forwardly of said groove, and the said contact housing having an outwardly flaring guide surface for guiding the trunnions into said groove and guiding the fuse tube unit between said legs.

6. In a contact arm structure for a fused dropout cut-out, the combination of an insulator with a clamping band embracing said insulator, said band havin a pair of attaching flanges, and means to draw said flanges together to clamp said band on said insulator, with a contact housing member comprising a metal member having a body provided with a pair of apertures, and threaded members passing through said apertures and attaching flanges to secure the contact housing to said clamping bandand insulator, said contact housin having a pair of forwardly extending parallel legs, and each leg being provided with a partially cylindrical groove for engagement with the trunnion of a fuse tube unit, when the fuse tube unit is located between said legs; the said threaded-members also supporting on each side of said contact housing a resilient spring, each of said springs having a curved portion for engagement about each of said threaded members, and having a forwardly projecting portion which extends over and beyond said groove in position so that the forwardly extending portions of said springs are spread from the grooves by the trunnions of the fuse tube unit as the trunnions move into said groove, where they are held by said springs, one of said apertures for said threaded securin means being enlarged to permit a pivotal movement on the other securing member so that the contact housing and spring may be adjusted by pivotal move- 13 ment to engage the trunnions of fuse tube units of different lengths.

7. In a contact arm structure for a fused dropout cut-out, the combination of an insulator with a clamping band embracing said insulator, said band having a pair of attaching flanges, and means to draw said flanges together to clamp said band on said insulator, with a contact hous ing member comprising a metal member having a body provided with a pair of apertures, and threaded members passing through said apertures and attaching flanges to secure the contact housing to said clamping band and insulator, said contact housing having a pair of forwardly extending parallel legs, and each leg being provided with a partially cylindrical groove for engagement with the trunnion of a fuse tube unit, when the fuse tube unit is located between said legs, the said threaded members also supporting on each side of said contact housing a resilient spring, each of said springs having a curved portion for engagement about each of said threaded members, and having a forwardly projecting portion which extends over and beyond said groove in position so that the forwardly extending portions of said springs are spread from the grooves by the trunnions of the fuse tube unit as the trunnions move into said groove, where they are held by said springs, one of said apertures for said threaded securing means being enlarged to permit a pivotal movement on the other securing member so that the contact housing and spring maybe adjusted by pivotal movement to engage the trunnions of fuse tube units of different lengths, the said contact housing having a rear- Wardly extending tail, and resilient means carried by the first-mentioned means for drawing the attaching flanges together and by one of said threaded members, to be engaged by the said tail, for urging said contact housing in one direction of pivotal movement.

8. In a fused drop-out cut-out, a lower contact arrangement comprising a contact fixture carried by an insulating tube and a contact arm mounted upon an insulator, a contact housing secured to said contact arm, said contact housing having a pair of forwardly extending legs provided with an open slot between them, and said contact housing having a pair of partially cylindrical grooves, one in each leg for receiving a trunnion, said contact fixture being receivable in said open slot between said legs, and having a spring housing provided with a pair of oppositely extending trunnions to be received in said partially cylindrical grooves, said contact housing being provided with a rear wall which extends upwardly and over a part of the spring housing, to act as a stop, so that the lower contact fixture engages said stop upon the blowing of a fuse, due to the jet action of the gases escaping from said tube, the said contact housing being secured to said contact arm by a pair of threaded members, and said threaded members also supporting a pair of contact springs, each of said contact springs having a portion arranged around the threaded members; and having a forwardly extending portion extending across said grooves to ho d the trunnions in said grooves.

9. In a fused drop-out cut-out, the combination of an insulating support with a pair of laterally projecting contact arms carried by said support, e ch of said contact arms being provided with forwardly open partially cylindrical grooves for receiving the upper and lower trunnions of a fuse tube unit resilient means carried b each of said contact arms for removably holding the said trunnions in said grooves, one of said contact arms being mounted for a limited pivotal movement on said insulating support, the said contact arms and resilient means being flared outwardly to provide guides on either side of a tapered opening leading to said grooves, and a fuse tube unit provided at its upper and lower ends with contact fixtures, the said Contact fixtures having laterally projecting trunnions, the said trunnions being guided into said tapered opening and into said grooves as the fuse tube unit is installed, and the said pivotally mounted contact arm moving to accommodate the spacing between the contact arms to the spacing between the upper and lower trunnions on the fuse tube unit.

19. In a fused drop-out cut-out, the combination of an insulating support with a pair of laterally projecting contact arms carried by said support, each of said contact arms being provided with forwardly open partially cylindrical grooves for receiving the upper and lower trunnions of a fuse tube unit, resilient means carried by each of said contact arms for removably holding the said trunnions in said grooves, one of said contact arms beingmounted for a limited pivotal movement on said insulating support, the said contact arms and resilient means being flared outwardly to provide guides on either side of a tapered opening leading to said grooves, and a fuse tube unit provided at its upper and lower ends with contact fixtures, the said contact fixtures having laterally projecting trunnions, the said trunnions being guided into said tapered opening and into said grooves as the fuse tube unit is installed, and the said pivotally mounted contact arm moving to accommodate the spacing between the contact arms to the spacing between the upper and lower.

trunnions on the fuse tube unit, the said pivotally mounted contact arm being provided with spring biasing means for urging the grooved part of the contact arm toward the grooved part of the other contact arm, and the grooves of said contact arms extending outwardly slightly beyond the trunnions which they receive to form a retaining shoulder outwardly of the trunnions, over which the trunnions may be forced during installation or removal.

11. Ina fused drop-out cut-out, the combination of an insulating support with a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cylindrical grooves opposing each other for opposing engagement with contact trunnions of complementary shape carried by a rigid fuse tube unit, the said rigid contact arms being secured by a pair of bolts to a clamping band carried by said insulating support, said clamping band having a pair of attaching flanges and said bolts passing through apertures in said contact arms and said atttaching flanges, one of said apertures being elongated about one bolt to permit a limited pivotal movement of the contact arm about the other bolt, a rigid fuse tube unit comprising an insulating tube for receiving a fuse, and, upper and lower contact fixtures carried by said tube, and bearing laterally projecting trunnions for engagement with said contact arm, one of said contact arms having an extension extending beyond said attaching bolts, and resilient means engagin said extension to urge the contact arms toward each other for urging 13 the grooves of the contact arms into engagement with the trunnions to retain the trunnions.

12. In a fused drop-out cut-out, the combinae tion of an insulating support with a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cylindrical grooves opposing each other for opposing engagement with contact trunni-ons of complementary shape carried by a rigid fuse tube unit, the said rigid contact arms bein se cured by a pair of bolts to a clamping band carried by said insulating support, said clamping band having a pair of attaching flanges and said bolts passing through apertures in said contact arms and said attaching flanges, one of said apertures bein elongated about one bolt to per mit a limited pivotal movement of the contact arm about the other bolt, a rigid fuse tube unit comprising an insulating tube for receiving a fuse, and upper and. lower contact fixtures carried by said tube, and, bearing laterally projecting trunnio-ns for engagement with said contact arm, one of said contact arms having an exten sion extending beyond said attaching bolts, and resilient means engaging said extension to urge the contact arms toward each other fol-urging the grooves of the contact arms into engagement with the trunnions to retain the trunnions, the said fuse tube unit having its trunnions on its upper and lower contact fixtures extending up: positely from both sides, and the said contact arms being bifurcated to receive the contact fixture parts between the forks of the contact arms with the trunnions engaging grooves on both sides of the fuse tube unit.

13. In a fused drop-out cut-out, the combination of an insulating support with a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cylindrical grooves opposing each other for opposin engagement with contact trunnions of complementary shape carried by a rigid fuse tube unit, the said rigid contact arms being secured by a pair of bolts to a clamping band carried by said insulating support, said clamping band having a pair of attaching flanges and said bolts passing through apertures in said contact arms and said attaching flanges, one of said apertures being elongated about one bolt to permit a limited pivotal movement of the contact arm about the other bolt, a rigid fuse tube unit comprising an insulating tube for receiving a fuse, and upper and lower contact fixtures carried by said tube, and bearing laterally projecting trunnions for engagement with said contact arm, one of said contact arms having an extension extending beyond said attaching bolts, and resilient means engaging said extension to urge the contact arms toward each other for urging the grooves of the contact arms into engagement with the trunnions to retain the trunnions, said fuse tube unit being provided with a spring pressed fuse ejector lever pivotally mounted on the lower contact fixture and formed with a cam for engaging the contact arm between two spaced legs, the movement of the fuse ejector lever upon blowing of a fuse camming the lower trunnions out of their grooves to release the fuse tube unit at its lower end.

14. In a fused drop-out cut-out, the combination of an insulating support with a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cy lindrical grooves opposing each other for ope posing engagement with contact trunnions of complementary shape carried by a rigid fuse tube unit, the said rigid contact arms being secured by a pair of bolts to a clamping band carried by said insulating support, said clamping band having a pair of attaching flanges and said bolts passing through apertures in said contact arms and said attaching flanges, one of said apertures being elongated about one bolt to permit a limited pivotal movement of the contact arm about the other bolt, a rigid fuse tube unit comprising an insulating tube for receiving a fuse, and upper and lower contact fixtures carried by said tube, and bearing laterally projecting trunnions for engagement with said contact arm, one of said contact arms having an extension ex tending beyond said attaching bolts, and resilient means engaging said extension to urge the contact arms tow rd each other for urging the grooves of the contact arms into engagement with the trunnions to retain the trunnions, and a air of Conta p n a h. spring b in pr vided with looped portions for engagement about both of said bolts, and the springhaving a forwardly extending portion resiliently engaging the adjacent trunnion and urging it into the groove in the contact arm. I

15. In a fused drop-out cut-out, the combina tion of an insulating support with. a pair of rigid contact arms carried by said support in spaced relation to each other, the said contact arms being provided at their ends with partially cylindrical grooves opposing'each other for 012-- posing engagement With contact trunnions of complementary shape carried by a rigid fuse tube unit, the said rigid contact arms being secured by a pairof bolts to a clamping band carried by said insulating support, said clamping band having a pair of attaching flanges and said bolts passing through apertures in said contact arms and said attaching flanges, one of said apertures being elongated about one bolt to permit a limited pivotal movement of the contact arm about the other bolt, a rigid fuse tube unit com prising an insulating tube for receiving a fuse, and upper and lower contact fixtures carried by said tube, and bearing laterally projecting trunnions for engagement with said contact arm, one oi said contact arms having an extension ext tending beyond said attaching bolts, and resilient means engaging said extension to urge the con tact arms toward each other for urging the grooves of the contact arms into engagement with the trunnions to retain the trunnions, and a pair of contact springs, each spring being provided with looped portions for engagement about both of said bolts, and the spring having a forwardly extending portion resiliently engaging the adjacent trunnion and urging it into the groove in the contact arm, the contact arm also supporting an upper leaf spring formed with a shoulder resting on the end of the fuse tube unit, the said shoulder hooking over the corner of the fuse tube unit when the fuse tube unit is released at the lower contact arm to hang vertically by gravity, to hold the fuse tube unit against swinging in that position.

16. In a contact arm structure for fuse tube units, the combination of an insulator with a partially cylindrical band extending about said insulator and having laterally projecting spaced attaching flanges, threaded means passing hro h sa l es adjacen the insulator for clamping the band on the insulator, said laterally projecting flanges being provided with a pair of holes in each flange, a contact arm comprising a metal member formed with a yoke and having two parallel outwardly extending legs, the said yoke carrying a pair of attaching flanges with apertures registering with the said holes, a pair of through bolts extending through the attaching flanges of the yoke and the attaching flanges of the band to secure the contact arm to the band, the legs of said contact arm being provided adjacent their ends with a partially cylindrical groove in each leg, the grooves facing toward the other end of the insulator, and a pair of spring retainers, each spring retainer cornprising a wire having a pair of loops for looping about the latter bolts, the said wires extending outwardly along the legs of the contact arm and engaging the contact arm at the open side of said grooves, the legs of the contact arm having outwardly beveled surfaces extending away from the wires, outwardly of said grooves to guide a pair of trunnions into the grooves between the wires and the legs of the contact arm.

17. In a contact arm structure for fuse tube units, the combination of an insulator with a partially cylindrical band extending about said insulator and having laterally projecting spaced attaching flanges, threaded means passing through said flanges adjacent the insulator for clamping the band on the insulator, said laterally projecting flanges being provided with a pair of holes in each flange, a contact arm comprising a metal member formed with a yoke and having two parallel outwardly extending legs, the said yoke carrying a pair of attaching flanges with apertures registering with the said holes, a pair of through bolts extending through the attaching flanges of the yoke and the attaching flanges of the band to secure the contact arm to the band, the legs of said contact arm being provided adjacent their ends with a partially cylindrical groove in each leg, the grooves facing toward the other end of the insulator, and a pair of spring retainers, each spring retainer comprising a wire having a pair of loops for looping about the latter bolts, the said wires extending outwardly along the legs of the contact arm and engaging the contact arm at the open side of said grooves, the legs of the contact arm having outwardly beveled surfaces extending away from the wires, outwardly of said grooves to guide a pair of trunnions into the grooves between the wires and the legs of the contact arm, the said wires being also outwardly bent away from each other outwardly of said grooves to provide a flaring opening between the wires for guiding a fuse tube unit into the space between the legs of the contact arm.

18. In a contact arm structure for fuse tube units, the combination of an insulator with a partially cylindrical band extending about said insulator and having laterally projecting spaced attaching flanges, threaded means passing through said flanges adjacent the insulator for clamping the band on the insulator, said laterally projecting flanges being provided with a pair of holes in each flange, a contact arm comprising a metal member formed with a yoke and having two parallel outwardly extending legs, the said yoke carrying a pair of attaching flanges with apertures registering with the said holes, a pair of through bolts extending through the attaching flanges of the yoke and the attaching flanges of the band to secure the contact arm to the band, the legs of said contact arm being provided adjacent their ends with a partially cylindrical groove in each leg, the grooves facing toward the other end of the insulator, and a pair of spring retainers, each spring retainer comprising a wire having a pair of loops for looping about the latter bolts, the said wires extending outwardly along the legs of the contact arm and engaging the contact arm at the open side of said grooves, the legs of the contact arm having outwardly bev eled surfaces extending away from the wires, outwardly of said grooves to guide a pair of trunnions into the grooves between the wires and the legs of the contact arm, the said yoke of the contact arm having an extension extending toward said'insulator and provided with a spring engaging transverse flange extending in the same direction as the open side of the grooves, and spring means supported between the clamping bolt of the band and one of the other bolts and engaged by said transverse flange to urge the contact arm pivotally upon the adjacent bolt, in the direction in which the grooves are open, the other securing bolt for the contact arm having an elongated slot to permit a limited pivotal movement.

19. In a fused drop-out cut-out, the combination of an insulator with a pair of laterally projecting contact arms carried by the insulator, said contact arms having a pair of spaced parallel legs in each case and the legs of the contact arm having grooves in the top arm, and grooves in the bottom arm in both legs and the grooves facing toward each other, a fuse tube unit comprising an insulating tube and a contact fixture carried by each end of the tube, and oppositely extending trunnions on each side of each contact fixture for engaging in the partially open grooves of the contact arm legs when the fixture is between said legs, the upper contact arm having spring means below each groove for retaining the trunnions pivotally in the upper grooves, fuse actuated means for camming the lower contact fixture trunnions out of the lower grooves to permit the fuse tube unit to swing pivotally by gravity on its upper trunnions, the fuse tube being open at its lower end, resulting in jet action, and the upper trunnions being located on the outer side of the upper contact fixture so that the jet action on the tube tends to cause a clockwise rotation of the fuse tube unit on the upper trunnions, tending to retain the fuse tube unit in engagement with the lower contact arm until jet action has ceased.

DAVID C. HUBBARD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,953,136 Steinmayer Apr. 3, 1934 2,003,768 Boll et a1. June 4, 1935 2,212,633 Bodendieck Aug. 27, 1940 2,247,701 Ramsey July 1, 1941 2,310,466 Schultz et a1 Feb. 9, 1943 2,446,675 Yonkers Aug. 10, 1948 2,461,898 Hubbard Feb. 15, 1949 

